Every year in Major League Baseball a handful of players take their game up a notch or two and post star-level numbers after falling somewhere between pedestrian and downright awful the previous season. Some of those that do so come as no surprise, as often they are young players starting to live up to expectations.

As Chris Moran did with starting pitchers here, Prospect Insider’s Brendan Gawlowski discusses the most likely hitters to break out and significantly improve from 2013.

1. Bryce Harper, LF — Washington Nationals
Could it be anyone else? It’s incredible that someone who has been in the sport’s collective conscience since his SI Cover debut in 2009 could still be just 21-years-old, but with a major step forward, Harper could go from being the league’s youngest player to being the circuit’s best.

It’s fun to play around with Harper’s age contemporaries. Of all players in the history of baseball, only Mel Ott, Ty Cobb, and Al Kaline earned more WAR before they turned 21 than Harper, while Mickey Mantle and Ken Griffey Jr. sit just behind him. Switch the category from WAR to wRC+, and the order goes Ott-Cobb-Kaline-Conigliaro-Harper. That’s three inner-circle Hall of Famers and a player who was well on his way to superstardom before a tragic beaning devastated his career. Additionally, only Ott and Conigliaro had more homers or a higher ISO than what Harper has posted thus far. And needless to say, Harper is playing against significantly better competition than either.

Harper has both the pedigree and the exuberance to become the league’s best player at some point, and there’s really no reason why this couldn’t be the year he turns a big corner. He’s already among the best players in baseball: if he stays healthy, and sees any improvement in either his walk rate or his power numbers, he could be a legitimate MVP candidate on one of the best teams in the league.

2. Giancarlo Stanton, RF — Miami Marlins
At first glance, it might seem a bit strange to see a player with Stanton’s pedigree on a list like this. After all, he already has 2,000 plate appearances, 117 homeruns, and a 5-WAR season under his belt.

But after Stanton’s worst full season yet, a year where he struggled with injuries and announced he was pissed off in Miami, it’s clear that we can expect more from the Marlins franchise player. He has the most raw power in the sport, was third in all of baseball in average home run distance a year ago, and seems to be learning how to take a walk too. Stanton is still just 24-years-old, and possesses every bit as much potential as he ever has. So while it’s possible that he may never develop into an elite player, the evidence suggests he’s on the cusp of becoming the premier power hitter in the National League.

3. Jurickson Profar, SS — Texas Rangers
This list has a clear bias: former top prospects who have yet to establish themselves as stars are littered all over this rundown. Nobody fits that description better than Profar, who spent 2013 toiling behind Elvis Andrus and Ian Kinsler in Texas, and in a grander sense, languishing in comparison to youngsters like Manny Machado, Bryce Harper, and Mike Trout.

It’s important to remember that Machado, Harper, and Trout are fabulous talents coming off historic seasons; they absolutely should not set the barometer for which rookies should be judged against. Profar, who isn’t nearly as physically imposing as the aforementioned trio, will likely take longer to grow into his own as a player. And that’s fine, especially since the skills that vaulted him to the top of prospect lists a year ago are still apparent: his lateral range is still tremendous, he has a good arm, and it isn’t hard to see him cranking 15-20 homers out of his wiry frame. Look for Profar to establish himself as a first division with a full season at the keystone.

4. Anthony Rizzo, 1B — Chicago Cubs
First the downside: Rizzo has things to work on. Mechanically, he has too many moving parts in his swing, and it’s mystifying out how he hits with his hands so low. He’s also going to turn 25 this year, and after 1,200 career plate appearances, he has an exactly average career wRC+.

For all the bad though, Rizzo has the talent and — reportedly — the makeup to take a big leap forward in 2014. While 2013 was a disappointment on the surface, he improved his walk rate and ISO from 2012, and his numbers were partially restrained by a fluky .258 BABIP. Rizzo isn’t going to win any batting titles, but not he’s not an all-or-nothing fly ball hitter either, so some positive regression in this category should help. When he’s right, Rizzo is capable of launching balls into the right field bleachers, and Rotographs’s Chris Cwik smartly noted that his best periods last year correlated with when he was hitting plenty of fly balls. If he can keep his swing consistent for a full season, he could hit 30 homers.

5. Christian Yelich, OF — Miami Marlins
The hit tool is possibly the most difficult element of a hitter’s profile to project accurately. Anyone who has spent much time watching Dustin Ackley — or Justin Smoak or Josh Vitters or any other number of young hitters — knows how misleading the phrase “can’t miss bat” can be when it comes to young talent.

It would be unfair to allow the fickleness of the hit tool diminish our expectations for Yelich, however, particularly considering how impressive he was in his debut season. Last year, Yelich quietly posted a 116 wRC+ after a midseason call up, making him one of just a couple dozen players to hit that well as a 21-year old over the last few decades. As you might expect, that list is chock-full of luminaries and all-stars.

We shouldn’t overreact to 250-plate appearances, nor ignore Yelich’s flaws, specifically his propensity to strike out. The former first round pick whiffed in nearly a quarter of his plate appearances last year, far too often for a player who hasn’t developed much power yet. Still, his strikeouts stem from a willingness to be patient and work the count, and not from a bad approach, which implies that he could improve in this regard as soon as 2014.

6. Desmond Jennings, CF — Tampa Bay Rays
At age 27, there’s a chance that Jennings simply is what he is: an above average center fielder who doesn’t do quite enough in the field or at the plate to be considered a legitimate star. Over the past two years, he’s drawn a decent number of walks, hit for some power, and been a devil on the bases, but has never quite reached the heights of his 2011 rookie season, when he accrued 2.3 WAR in only 63 games.

Solid improvement across the board last year suggests that 2014 could be a breakout year for Tampa Bay’s center fielder. Jennings posted career best walk and strike out ratios last year while improving his ISO and slugging percentage from 2012. He also bounced back well from a fractured finger, hitting .288/.414/.521 in September. Even as he played through pain in August, he struck out as often as he walked, and actually posted a 37/47 BB/SO ratio July through September. If he can maintain that kind of plate discipline over a full season — Jennings has never played 140 games — while hitting for a bit more power, he could emerge as a five win player for a very competitive Tampa Bay team.

7. Brett Lawrie, 3B — Toronto Blue Jays
Unlike most players on this list, Lawrie’s placement here reflects more on his obvious physical gifts than his recent big league track record. On a tools basis, Lawrie has few peers in the league. He possesses tremendous raw power, a great arm, fantastic bat speed, and a good feel for contact.

Part of Lawrie’s struggles — “struggles” being relative, as a career 106 wRC+ is nothing for a 23-year-old third basemen to sneeze at — at the plate have stemmed from his tendency to expand the zone. He’s not Starlin Castro, but Lawrie likes to swing, and he has good enough hand-eye coordination to reach pitches out of the strike zone. It’s a mixed blessing: Lawrie reaches a lot of what he chases, but he’s also made plenty of weak contact lately, which has hurt his BABIP and his entire offensive profile. Given his raw power and hitting ability, he stands to benefit more than most from improved plate discipline. If the Canadian takes a step forward in this department, he’s an all-star.

Above are the core offensive numbers for two rookie second basemen. They took slightly different paths to accrue similar value, but at a casual glance, Gyorko looks like the better player. So why is Rendon on this list while the Padres’ sophomore isn’t?

It essentially comes down to three things. One, Rendon projects better defensively. A natural third basemen, Rendon impressed at the keystone after he was thrust into action last year, and his performance indicates that he can hold down either position defensively. Two, Rendon is only 23-years-old and is nearly two years younger than Gyorko. And three, as a corollary to that last point, Rendon has plenty of offensive development left in his game. He was a power hitter in college and showed decent thump in limited minor league action. As he ages, he’ll turn some of his doubles into homers, and if he stays healthy, he could be a monster player at an impact defensive position. Gyorko, by contrast, is almost a finished product. So while he’s certainly a good player and might even post better numbers in 2014, Rendon is the better bet to settle in as a perennial all star, and he might do so as soon as this season.

9. Brad Miller, SS — Seattle Mariners
On talent, this spot would have come down to a coin flip between Miller and his teammate/friend Nick Franklin. Given the latter’s murky situation in Seattle though, Miller gets the nod. At the end of the day, Miller’s the superior defensive shortstop and even if he isn’t plus at the position, he should have enough range to hold his own with the glove.

Ultimately, Miller will be judged by his stick, and in that department, so far so good. He posted a 103 wRC+ in 76 games last year, a figure just three full-time shortstops topped last season. Furthermore, Miller doesn’t really have a bad split or a pronounced weakness: he walks a little, hits for more pop than a typical shortstop, and won’t get beat up too badly by left handed pitching. He could stand to be a bit more disciplined: after walking in about 12 percent of his minor league plate appearances — and initially showing patience at the highest level — Miller expanded the zone at times down the stretch. He had good plate discipline as a minor leaguer and if he develops in that area, there’s no reason he can’t spend the next several seasons as an above average hitter at a premium defensive position.

10. Kole Calhoun, OF — Los Angeles Angels
Perhaps the least heralded player on this list, Calhoun has the perennially underrated “good at everything, great at nothing” skillset. If everything breaks right, Calhoun could turn into one of those late bloomers who makes everyone wonder why he never graced a top prospect list on his way up through the minors. Unlike most of the players on this list, Calhoun is already in his physical prime so it’s not unrealistic to think he could hit 15-20 homers with a .350 OBP and decent defense in right field. That’s a good player, and if Mike Scioscia lets him lead off, he might wind up running a bit more, too.

Not So Fast
Below are a group of candidates one might believe are in line for a step forward, whether that be due to another year of valuable experience, physical maturation or a rebound season from a veteran. We’re here to warn you not to bet on any of them with confidence.

Manny Machado, 3B — Baltimore Orioles
Machado isn’t a bad player and he isn’t due for any kind of major homerun or BABIP regression: he’s on this list simply because he already has broken out. Sure, there may be some room for Machado to improve upon his offensive numbers — he faded significantly at the plate down the stretch, hitting just .239/.272/.366 after June — but it’s also fair to say that his hacktastic ways limit his upside at the plate.

Machado has walked in just four percent of his big league plate appearances thus far, and to the extent that players improve their walk rate over their careers, such progress tends to be gradual. Between that and the fact his defensive numbers are unlikely to improve — he was worth nearly 3.5 wins with the glove last year — Machado is unlikely to take his game to another level in 2014.

Yasiel Puig, RF — Los Angeles Dodgers
For a moment, forget about Puig’s conditioning concerns. Those are certainly valid of course, and there’s a decent chance that the Cuban’s extra weight will have a debilitating effect on his production, particularly in the field. The thing is though, Puig belonged on this list before he surprised everyone by showing up to camp 25 pounds overweight this February.

Like Machado, he’s here because he already did break out. He posted 4 fWAR in only 104 games a season ago; prorate that pace over 150 games, and Puig would have been nearly a six win player. Essentially, a full season of 2013 Puig would have been a fringe MVP candidate. To break out, he’d have to significantly outproduce those numbers, and his profile doesn’t suggest he’s going to turn into Mike Trout 2.0. Despite his arm strength, he’s not a premium defender, he doesn’t walk much, and even if he hits everything he reaches again, he’ll be hard pressed to bat more than .380 on balls in play like he did a year ago.

Freddie Freeman, 1B — Atlanta Braves
Young sluggers with a history of high batting average and superb RBI production are excellent candidates for MVP Awards, particularly if they play for title contenders, as Freeman does. And now that the Braves are paying their first-sacker like an MVP candidate, pundits and fans alike are sure to have big expectations for Freeman.

There are reasons to think, however, that Freeman reached something close to his offensive ceiling last year. With the caveat that Freeman is just 25 and could still develop power in time, it appears that he is settling in as a 20-25 homer guy, and probably won’t add much thump on top of that. His swing is much more compact than a traditional slugger’s cut, and while he offers enough strength, loft, and bat speed to hit his fair share of homers, it’s hard to see him augmenting his power without adding some length to his swing. So, if he’s reached his power ceiling, he’s going to need a lot of line drives to fall in to be an elite offensive player. He hit .371 on balls in play last year, and if he takes a step back in that department, his overvalue will likely decline correspondingly.

Nelson Cruz, OF/DH — Baltimore Orioles
This section has had a decidedly ‘he played well last year so expect regression’ flavor to it thus far, so let’s nip that trend here. There’s a narrative swirling that Cruz, upset that he had to sign a contract worth a fraction of the $75 million deal he reportedly coveted, will join the Orioles as a motivated man and once again become the right fielder he was at his peak in 2009 and 2010, when he combined power with solid-average defense.

The problem with this theory lies less in Cruz’s mental state than his declining skillset. Advanced metrics say he’s been bad in the field since 2010, and even when UZR liked him, Cruz was a case where the eyes and the numbers didn’t quite align. Always a questionable route runner, Cruz is slower now than he was in his prime, and should probably spend most of his time as a DH, where he doesn’t have enough stick to be considered an impact player. He’s also only topped 130 games played once in his career, so even if he does bounce back a bit history suggests he won’t play enough to recapture his previous value.